Smoking cigarettes and alcohol addiction are serious problems in health hazard and life of society. Tobacco smoke leads to many kinds of cancer formation and scientific research indicates, that heart-vascular disease and lung cancer are the most common diseases caused by tobacco smoke. While talking about ethanol, it is responsible for liver, pancreas, mucous membrane damage and leads to central and circular nervous disorder. Scientific research indicates, that many smokers drink alcohol and vice versa. Unfortunately in that case the risk of many diseases increases. Both of these stimulants leads to enlarged production of reactive oxygen species, which is connected with unbalance between pro and antioxidant processes in human organism. Free radicals in normal conditions plays positive role but with tobacco smoke and alcohol connection may lead to serious changes in human organism. They damage organs, it comes to protein structure, nucleic acid and fat violation, which in consequence leads to immunity decrease and many pathological changes. Reactive oxygen species also plays role in pathogenesis of many diseases: diabetes mellitus, atherosclerosis and Down syndrome. ROS may also increase the risk of pancreas, lung, larynx and urinary bladder cancer formation. Human organism defends oneself from harmful influence of reactive oxygen species owing to enzymatic and non-enzymatic systems presence-Non-enzymatic antioxidants: glutathione, carotene, bilirubin, tocopherol, uric acid and ions metals temporary complex belong to non-enzymatic systems. To enzymatic ones belong: catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase. The aim of the study was tobacco smoke and ethyl alcohol influence evaluation in rats addicted to these substances on activity of chosen enzymes responsible for organism defense against toxic compounds action. To this study 63 white, Wistar tribe rats at the age of 3,5 months were used - males addicted to ethyl alcohol. They were divided into 3 groups, each consist of 21 rats. Animals of Group I were exposed on harmful tobacco smoke influence. Group II constitute animals, which were given by stomach probe 10% alcohol dilution once at a dose of 2 g/kg weight. The next Group - III, in which animals at first were exposed on tobacco smoke influence. When exposition was over, animals were given by stomach probe 10% alcohol dilution once at a dose of 2 g/kg weight. Depending on the type of marker and studied organ, changes in the levels of selected enzymes, responsible for defending organism against reactive forms of oxygen has been shown. Both tobacco smoke and ethyl alcohol resulted in a change of glutathione levels in the serum and tissues of animals. Tobacco smoke has the biggest influence on protein nitrozylation in the brain and ethyl alcohol had influence on glutathione level in serum, kidney, brain and superoxide dismutase activity in the brain. Application of many oxidative stress markers allows for evaluation of its differential influence on various organs.